Abstract

Economic and environmental considerations in the production of soft red winter wheat (Triticum aestivum L.) dictate that applied N fertilizer be used efficiently. This study was conducted to compare split, spring N applications with standard, single applications of spring N during the wheat tillering phase (Zadoks growth stage 23–27, Feekes 2–3). Experiments were conducted during two years on State sandy loam soils (mixed, thermic, fine-loamy Typic Hapludults) in the Atlantic Coastal Plain. Spring N rates of 80 and 120 lb N/acre were applied once at growth stage 23–27 or in various combinations at growth stages 23–27, 45 (Feekes 10, “boots” swollen), and 58 (Feekes 10.5, immediately prior to flowering). Splitting spring N applications at both N levels increased yields relative to single N applications in one year, with yield increases ranging from 3 to 12%. No differences were found between the two-split or three-split treatments. Lodging decreased in both years, when split spring N applications were compared with the single tillering-phase applications. Total N and P uptake increased with splitting spring N. Potassium uptake was unaffected by splitting the N applications in 1982, but in 1983 the single N applications increased K uptake due to greater straw production. Split spring N applications may increase yield in some seasons, and should be considered in soft red winter wheat production on soils where the probability of leaching or denitrification losses of N applied during the tillering phase is high, or where wheat has a history of lodging. Further research is being conducted to determine if other growth stages are more optimum for spring N applications.

Copyright © 1988. . Copyright © 1988 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, 5585 Guilford Rd., Madison, WI 53711 USA